1. Field of the Invention
The present invention relates to a method of growing a nanowire array, and more particularly, to a method of manufacturing a nanowire array using induced growth, in which nanotunnels are formed by using an organic nanowire array as a template and an aligned inorganic nanowire array is then formed by induced growth through the nanotunnels.
2. Description of the Related Art
Semiconductor nanowires, as an advanced device that may exceed the limitations of conventional semiconductor technology, have been recognized as an innovative key technology in various semiconductor application areas and have been particularly in the spotlight in electronic and optical device applications. In the electronic device applications, a significant amount of research related to transistors and memory devices using nanowires has been conducted. Research into solar cells and light-emitting devices in the optical device applications and research using nanoscale material characteristics in a laser field have been actively conducted, and particularly, excellent semiconductor characteristics of a one-dimensional nanostructured semiconductor have been reported.
However, inorganic semiconductor nanowires (Group IV semiconductors and compound semiconductors), which have been typically reported, are typically grown in a vertically aligned structure, and accurate length and diameter control may not only be difficult, but it may also be impossible to accurately adjust the number of nanowires. In particular, even if an array having a vertically aligned structure is grown, it is highly difficult, in terms of processing, to apply the individual nanowire or nanowire array to an optical device or electronic device. When the formation of a horizontal array as well as the adjustment of individual structure or position of the nanowire is possible, a nanowire device may be actually used.
Thus, there has been a lot of efforts to constantly align nanowires at a desired position. There are two main methods of obtaining aligned nanowires which include (i) a method of using an alignment process after the growth of nanowires, and (ii) a method of directly growing aligned nanowires. The alignment of nanowires may be performed in such a manner that nanowires are dispersed in a solution and the nanowires are aligned by using fluidic channel, Langmuir-Blodgett, blown-bubble, contact printing, and electromagnetic field. Also, in a case in which a nanowire array is directly grown, a method of making a growth template through pre-patterning is used. For example, in growing vertical nanowires through vapor-liquid-solid (VLS) growth, when catalysts are prepared through a method, such as electron beam lithography or deep ultraviolet lithography, and nanowires are then grown, a vertically aligned nanowire array is formed only at a position patterned in advance. However, the method has limitations in that the patterning method may be difficult to provide a large-area pattern, may be expensive, and may only provide the array having a vertically aligned shape. Recently, professor Tsivion et al. have succeeded in directly growing horizontally aligned nanowires on a substrate using a miscut of the substrate (see D. Tsivion, M. Schvartzman, R. Popovitz-Biro, P. von Huth, E. Joselevich, Σχι∈νχ∈, 333, 1003(2011)). Although it is a very successful method in terms of the fact that gallium nitride nanowires may be grown on a sapphire substrate in a desired crystal direction, it is difficult to accurately control the number of nanowires as well as the diameter and length of the individual nanowire. In addition, the method may have a limitation in that crystallographically restricted planes may only be used in the growth.
Thus, in order to use an inorganic nanowire array in an actual device, there is a need to develop a method of forming nanowires which may accurately control the structure of the nanowire as well as crystal orientation. With respect to an organic nanowire technique, semiconductor properties of nanowires are inferior to those of a single crystal inorganic material. However, since flexibility may be excellent and the technique may have advantages such as mass synthesis, solution process, and low costs, there is a need to conduct continuous research.